WebControl
TM
PLC User Guide Version 3.02.17f
Copyright(c) 2008,-2013 CAI Networks, Inc. 18
4.2 Analog Inputs
WebControl
TM
has three built-in analog inputs each having an input voltage range of
0 to +10V. When a DS2450 chip is connected to the 1-wire bus, additional analog
input AIP5,6,7, and 8 are displayed. DS2450 chip has 10 bit resolution and full scale
voltage is 0 to +5.0V. Both built-in and optional DS2450 A/D inputs have the full
scale range of 0 – 1023. To reduce A/D noise, user may add a 470uF 6.3V capacitor
crossing 5V and ground terminal on the J12 header or temperature sensor terminal.
In PLC code, user can reference to the fourth analog input value AIP4, which is the
reading from humidity sensor.
4.3 DS1822/DS18B20 1 Wire Temperature Sensors
WebControl
TM
supports up to eight Maxim DS1822 /DS18B20 12bit 1 wire
temperature sensors. Each temperature sensor must be first assigned a temp sensor
number T1-T8.
Figure 10.0 WebControl
TM
Temperature sensor assignments
Each temp sensor has unique ROM code. One temp sensor can be assigned for
different sensor number. User can also select the unit as Centigrade or Fahrenheit. If
sensor failed later due to sensor failure or wire problem, WebControl
TM
will display
the state as failed, but keep the last valid sensor value. This is to prevent the PLC
logic turn on heater/cooler or motor undesirably.
